issue 3908
Missing space in (define-bar-line ":|]" ":|]" #f " |") caused bad
visual output of VoltaBracket.
Changed to (define-bar-line ":|]" ":|]" #f " | ")
The space added will cause that the SpanBar x-extent will be calculated
correctly to determine the gap between two VoltaBrackets.
(define-bar-line ":|." ":|." #f " |.")
(define-bar-line ".|:" "|" ".|:" ".|")
(define-bar-line "[|:" "|" "[|:" " |")
-(define-bar-line ":|]" ":|]" #f " |")
+(define-bar-line ":|]" ":|]" #f " | ")
(define-bar-line ":|][|:" ":|]" "[|:" " | |")
(define-bar-line ".|:-||" "||" ".|:" ".|")